import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../../domain/entities/meal_type.dart';
import '../controllers/nutrition_controller.dart';

/// Opens the interactive food logging dialog.
///
/// Resolves to `true` when the meal was persisted, `false` when saving
/// failed, and `null` when the user dismissed the dialog.
Future<bool?> showLogFoodDialog(
  BuildContext context, {
  MealType initialMealType = MealType.breakfast,
}) {
  return showDialog<bool>(
    context: context,
    builder: (context) => LogFoodDialog(initialMealType: initialMealType),
  );
}

/// Form for logging a meal: slot, description, protein, calories, and
/// optional carbohydrate/fat macros.
class LogFoodDialog extends ConsumerStatefulWidget {
  const LogFoodDialog({
    super.key,
    this.initialMealType = MealType.breakfast,
  });

  /// Meal slot pre-selected in the dropdown.
  final MealType initialMealType;

  @override
  ConsumerState<LogFoodDialog> createState() => _LogFoodDialogState();
}

class _LogFoodDialogState extends ConsumerState<LogFoodDialog> {
  late MealType _mealType = widget.initialMealType;

  late final TextEditingController _descriptionController =
      TextEditingController();
  late final TextEditingController _proteinController =
      TextEditingController();
  late final TextEditingController _caloriesController =
      TextEditingController();
  late final TextEditingController _carbsController = TextEditingController();
  late final TextEditingController _fatController = TextEditingController();

  final GlobalKey<FormState> _formKey = GlobalKey<FormState>();
  bool _isSaving = false;

  @override
  Widget build(BuildContext context) {
    return AlertDialog(
      title: const Text('Log Food'),
      content: SizedBox(
        width: 440,
        child: Form(
          key: _formKey,
          child: SingleChildScrollView(
            child: Column(
              mainAxisSize: MainAxisSize.min,
              crossAxisAlignment: CrossAxisAlignment.stretch,
              children: [
                DropdownButtonFormField<MealType>(
                  initialValue: _mealType,
                  decoration: const InputDecoration(
                    labelText: 'Meal',
                    border: OutlineInputBorder(),
                  ),
                  items: [
                    for (final type in MealType.values)
                      DropdownMenuItem(
                        value: type,
                        child: Text(type.displayName),
                      ),
                  ],
                  onChanged: (type) {
                    if (type == null) return;
                    setState(() => _mealType = type);
                  },
                ),
                const SizedBox(height: 16),
                TextFormField(
                  controller: _descriptionController,
                  decoration: const InputDecoration(
                    labelText: 'Description',
                    hintText: 'e.g. Greek yogurt with berries',
                    border: OutlineInputBorder(),
                  ),
                  textCapitalization: TextCapitalization.sentences,
                  validator: (value) => (value == null || value.trim().isEmpty)
                      ? 'Enter a description'
                      : null,
                ),
                const SizedBox(height: 16),
                Row(
                  children: [
                    Expanded(
                      child: TextFormField(
                        controller: _proteinController,
                        decoration: const InputDecoration(
                          labelText: 'Protein (g)',
                          border: OutlineInputBorder(),
                        ),
                        keyboardType: const TextInputType.numberWithOptions(
                          decimal: true,
                        ),
                        validator: _positiveDecimalValidator('protein'),
                      ),
                    ),
                    const SizedBox(width: 12),
                    Expanded(
                      child: TextFormField(
                        controller: _caloriesController,
                        decoration: const InputDecoration(
                          labelText: 'Calories',
                          border: OutlineInputBorder(),
                        ),
                        keyboardType: TextInputType.number,
                        validator: _nonNegativeIntValidator('calories'),
                      ),
                    ),
                  ],
                ),
                const SizedBox(height: 16),
                Row(
                  children: [
                    Expanded(
                      child: TextFormField(
                        controller: _carbsController,
                        decoration: const InputDecoration(
                          labelText: 'Carbs (g, optional)',
                          border: OutlineInputBorder(),
                        ),
                        keyboardType: const TextInputType.numberWithOptions(
                          decimal: true,
                        ),
                        validator: _optionalDecimalValidator('carbs'),
                      ),
                    ),
                    const SizedBox(width: 12),
                    Expanded(
                      child: TextFormField(
                        controller: _fatController,
                        decoration: const InputDecoration(
                          labelText: 'Fat (g, optional)',
                          border: OutlineInputBorder(),
                        ),
                        keyboardType: const TextInputType.numberWithOptions(
                          decimal: true,
                        ),
                        validator: _optionalDecimalValidator('fat'),
                      ),
                    ),
                  ],
                ),
              ],
            ),
          ),
        ),
      ),
      actions: [
        TextButton(
          onPressed: _isSaving ? null : () => Navigator.of(context).pop(),
          child: const Text('Cancel'),
        ),
        FilledButton.icon(
          onPressed: _isSaving ? null : _save,
          icon: _isSaving
              ? const SizedBox(
                  width: 16,
                  height: 16,
                  child: CircularProgressIndicator(strokeWidth: 2),
                )
              : const Icon(Icons.restaurant_menu),
          label: const Text('Log Food'),
        ),
      ],
    );
  }

  String? Function(String?) _positiveDecimalValidator(String field) =>
      (value) {
        final parsed = double.tryParse((value ?? '').trim());
        if (parsed == null || parsed < 0) return 'Enter a valid $field';
        return null;
      };

  String? Function(String?) _nonNegativeIntValidator(String field) =>
      (value) {
        final parsed = int.tryParse((value ?? '').trim());
        if (parsed == null || parsed < 0) return 'Enter a valid $field';
        return null;
      };

  String? Function(String?) _optionalDecimalValidator(String field) =>
      (value) {
        final raw = (value ?? '').trim();
        if (raw.isEmpty) return null;
        final parsed = double.tryParse(raw);
        if (parsed == null || parsed < 0) return 'Enter a valid $field';
        return null;
      };

  Future<void> _save() async {
    if (!(_formKey.currentState?.validate() ?? false)) return;

    setState(() => _isSaving = true);
    final saved = await ref.read(nutritionControllerProvider.notifier).logFood(
          mealType: _mealType,
          description: _descriptionController.text,
          proteinGrams: double.parse(_proteinController.text.trim()),
          calories: int.parse(_caloriesController.text.trim()),
          carbsGrams: double.tryParse(_carbsController.text.trim()),
          fatGrams: double.tryParse(_fatController.text.trim()),
        );
    if (!mounted) return;
    Navigator.of(context).pop(saved);
  }

  @override
  void dispose() {
    _descriptionController.dispose();
    _proteinController.dispose();
    _caloriesController.dispose();
    _carbsController.dispose();
    _fatController.dispose();
    super.dispose();
  }
}